Zeolite catalyzed conversion of acetylene

ABSTRACT

The invention relates to an efficient process for the production of higher hydrocarbon from the catalyzed conversion of acetylene. This invention describes the use of a nickel or cobalt-containing zeolite catalyst, coupled with the addition of a hydrogen donor co-reactant to the acetylene feed, to obtain continuous and complete conversion of acetylene to other hydrocarbons. The catalyst/reactant feed process described eliminates rapid catalyst deactivation.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a process for the continuous conversion ofalkynes to mixtures of aromatics, olefins and paraffins useful as fuelsor fuel additives. The process utilizes a shape selective zeolite,modified with a metal such as nickel or cobalt, and requires theaddition of a hydrogen containing co-reactant in order to achievecontinuous single-step conversion of alkynes to higher hydrocarbonproduct mixtures.

2. Description of Related Art

The continuous catalyzed conversion of acetylene to higher hydrocarbonshas been the subject of numerous studies (Tsai, P. and Anderson, 1983;Allenger, Fairbridge et al, 1987; Allenger, McLean et al, 1987;Allenger, Brown et al, 1988). Interest in this process reflects the factthat successful conversion of this type could serve as a possible sourceof synthetic fuel (Tsai and Anderson, 1983; Allenger, Fairbridge et al,1987; Allenger, McLean et al, 1987). The synthetic fuel possibility iscentered on the fact that acetylene is obtainable in industrialquantities from coal and methane (Tedeschi, 1982). However, as notedexplicitly by previous workers, the unavailability of an effectivecatalyst for continuous acetylene conversion has prevented developmentof this alternative fuel route (Tsai and Anderson, 1983; Allenger,Fairbridge et al, 1987; Allenger, McLean et al, 1987).

A difficulty encountered with acetylene, or other simple unsaturatedhydrocarbon feedstock conversions, is the rapid deactivation of thecatalysts employed. This loss of activity is believed to arise primarilyfrom the rapid polymerization of hydrocarbon feedstocks to polycyclicaromatics. These polycyclic aromatics serve as precursors to cokeformation and eventual catalytic deactivation. For example, there is anapproximate 70% decrease in acetylene conversion using a ZSM-5 catalystafter only 190 min of on-stream conversion at an acetylene spacevelocity of 460 hr⁻¹ and reaction temperature of 300° C. (Tsai andAnderson, 1983). Similarly, significant decreases in acetyleneconversion over amorphous fluorinated alumina catalysts with time onstream have been reported (Allenger, Brown et al, 1988). In the lattercase, catalytic deactivation increased rapidly with increasing acetyleneconcentration in the reactant stream. Similarly, the ZSM-5 catalyzedconversion of acetylene/hydrogen mixtures revealed a 46% decrease in C₂H₂ conversion (i.e. from 35.5% to 19%) after only 220 min of on-streamreaction (White et al., 1984).

Zeolite catalyst modification has been explored as a means to alteryield and distribution of aromatized product in feed stream effluents.Nickel-containing zeolites have been tested for ability to convertacetylene to gasoline grade fuel in a single step. Conversion wasobserved but the yields were low (Seddon, et al, 1986). Zeolitecontaining framework-incorporated iron is reported to be effective inthe conversion of acetylene plus hydrogen mixtures with or without thepresence of added water or methanol. However, the conversioneffectiveness of this iron containing zeolite is reported to be similarto that of ZSM-5, which exhibits rapid catalytic deactivation. (White etal., 1984) Zeolite catalysts in which cations have been exchanged withCr(+3) or Cr(+6) ions are known to catalyze the conversion of acetyleneto product mixtures containing benzene and alkyl aromatics; however, thecatalyst again exhibits rapid deactivation (Chevreau, 1988).

Thus, all previous attempts to achieve continuous catalyzed conversionof acetylene have reported rapid catalytic deactivation. In each case,this loss of catalytic activity is believed to arise from the formationof polycyclic aromatics which, in turn, lead to coke formation on thecatalysts. Coke formation in the form of polycyclic aromatics isgenerally acknowledged to be the prime cause of the surface deactivationof zeolites with consequent decreases in conversion yields.

The desirability of high monocyclic aromatic hydrocarbon content in theacetylene conversion product distribution is based on theoctane-enhancing properties of these compounds with respect to theproduction of synthetic fuels. This property of aromatics is importantbecause of the relatively low octane number of unleaded gasoline due toprohibition of tetraethyl lead addition to increase octane ratings.Therefore efficient processes to provide gasoline fuel mixturescontaining aromatics are being sought. Clearly, with respect to theutilization of acetylene for synthetic fuel production, a key aspect ofthe catalytic conversion upgrade is to generate significant quantitiesof monocyclic aromatics while simultaneously minimizing formation of thepolycyclic aromatics which lead to the catalyst deactivation. Thiscatalyst deactivation has plagued previous attempts at continuousacetylene conversion.

SUMMARY OF THE INVENTION

The present invention is intended to address one or more of the problemsencountered in attempting to achieve efficient catalyzed conversion ofacetylene or acetylene containing mixtures to lower hydrocarbon fuels.This invention demonstrates that a shape selective zeolite catalyst(e.g. ZSM-5) when appropriately modified by loading with a metal (e.g.nickel or cobalt) is able to catalyze continuous conversion of acetyleneto higher hydrocarbons when an appropriate hydrogen atom donor is addedto the acetylene flow stream. Most importantly, this inventiondemonstrates that water functions effectively as a hydrogen atom donor.Additional potential hydrogen atom donors include reactants such ashydrogen, methanol, ethanol, and acetaldehyde. As clearly demonstratedby control experiments, both the added metal atom loading of thecatalyst and the addition of the sacrificial hydrogen atom donor to theacetylene flow stream are required in order to maintain continuouscatalytic conversion activity. Using this reactant combination, there islittle or no loss of catalytic activity during the conversion. Reactionconditions may be manipulated to alter product ratios, particularly toincrease the percentage of monocyclic aromatics in the product mixture,thus enhancing potential usefulness as a gasoline fuel or fuel additive.

Overall and in general, the invention comprises a highly efficientprocess for producing a hydrocarbon fuel. The process is basically asingle step involving contacting a feedstock with a metal-containingzeolite catalyst. The feedstock is an alkyne in combination with wateror other potential hydrogen atom donors such as methanol, ethanol,propanol, lower molecular weight aldehydes, ketones, acids and the like.It has been found that an alkyne hydrocarbon mixed with water or analcohol, for example, in the presence of a metal-containing zeolitecatalyst such as Ni/ZSM-5/Al₂ O₃ will maintain virtually 100% conversionto higher hydrocarbon products over a relatively long period of timewith no substantial deactivation or poisoning of the catalyst.

Low molecular weight alkynes may be used as feedstock components in thisprocess. Examples include acetylene, propyne, 1-butyne, and 2-butyne andthe like. Selection of the alkyne is generally made on the basis ofeconomic considerations, with acetylene as a preferred feedstock.Acetylene is readily available, inexpensive and the products resultingfrom its conversion over the zeolite catalyst are generally consideredmore economically valuable than acetylene itself. Acetylene is readilyavailable from coal and from natural gas. Acetylene production from coalis achieved via the intermediary formation of calcium carbide as follows(Tedeschi, 1982):

    CaCO.sub.3 →CaO+CO.sub.2

    CaO+coal→CaC.sub.2 +CO

    CaCl.sub.2 +H.sub.2 O→Ca(OH).sub.2 +C.sub.2 H.sub.2

The CaO feedstock is replenished by dehydration of the Ca(OH)2 Thus theC₂ H₂ production can be viewed simply as a coal+H₂ O reactant feedconversion process. Alternately, acetylene can be produced fromhydrocarbons by short (millisec) high temperature pyrolysis of alkanes(e.g. CH₄) followed by rapid thermal quenching to stabilize theacetylene formed (Tedeschi, 1982). This acetylene from alkane synthesisis illustrated for methane as follows:

    2CH.sub.4 →C.sub.2 H.sub.2 +3H.sub.2

An important aspect of the invention is the combination of a hydrogendonating compound, such as water, with the basic acetylene feedstock.Other compounds such as hydrogen, alcohols, aldehydes, ketones and acidscan also be employed for this purpose. Water is especially preferred forthis purpose. The basis of this preference is the availability andcheapness of water, as well as the relatively high product yield ofmonocyclic aromatic hydrocarbons produced with this reactant. Thepresence of water, or other hydrogen donating reactants as noted above,or combinations of these reactants in the feedstock mix is believed tobe important because it prevents polymerization of the feedstockhydrocarbon into condensed aromatic ring compounds which may lead tocoke formation. Zeolite catalysts are known to be particularlysusceptible to poisoning from coke formation.

Surprisingly, unmodified zeolite catalysts do not provide continuousefficient catalytic conversion of acetylene, even when the appropriatehydrogen donor co-reactant is added to the reactant feed. However,loading the zeolite catalyst with a metal such as nickel or cobaltprovides efficient conversion of acetylene feedstocks when the addedhydrogen donor reactant is also present. It is well documented thatzeolite catalysts used in conversion of acetylene to higher hydrocarbonsare poisoned and have a relatively short lifetime. This poisoning isobserved even when relatively large amounts of hydrogen are added to theacetylene feedstock (White, 1984). It is believed that polymerizedaromatic hydrocarbons adhere to the catalytic surface blocking access ofthe reactant molecules to the active sites.

Unexpectedly, nickel and cobalt-modified ZSM-5 zeolite catalyzedconversions of acetylene/H₂ O feedstocks proceed efficiently for longperiods of time. Nickel-containing ZSM-5 is a preferred catalyst whenmore than 5% nickel is present. In a most preferred embodiment, thecatalyst contains about 13% nickel. This is not to say that in someapplications higher nickel concentrations would not be preferred,particularly in view of the comparable results obtained with nickelloading of ZSM-5 up to 20%.

It has been found that a metal loaded zeolite catalyst and addedhydrogen donating reactant are required in order to achieve an efficientcontinuous conversion of acetylene. In the presence of an unmodifiedZSM-5 catalyst (that is, one without added metal atom loading), catalystdeactivation is rapid even when water and/or methanol and/or hydrogen isadded to the acetylene feedstock. In the absence of the metal loading ofthe catalyst, unsaturated lower molecular weight feedstock hydrocarbonssuch as acetylene polymerize to form coke precursors. However, it isalso important to note that in the absence of the added hydrogen donorreactant (e.g. water), the metal loaded zeolite catalytic activitydecreases rapidly with time on stream in the conversion of pureacetylene. Thus both the metal atom loading of the zeolite and theaddition of a co-feed hydrogen donor reactant are required in order toeliminate catalyst deactivation. The presence of the metal atoms (e.g.nickel) combined with the added hydrogen donor reactant (e.g. water)apparently function to limit the formation of structures having highcarbon to hydrogen ratios, particularly fused-ring compounds.

Although the invention has been demonstrated with nickel orcobalt-containing zeolite catalyzed conversion of alkyne feedstocks,other transition metals could be expected to replace nickel or cobalt.Catalytic properties of transition metals are well known and othermetals such as zinc, chromium, iron, copper, platinum, palladium, gold,rhodium, and the like could be introduced into the zeolite and reducedto deposit the metal onto the framework.

The feedstock used in the disclosed process is heated to a relativelylow temperature of 300°-400° C. Higher temperatures are not required inorder to maintain conversions near 100%. Furthermore, increasedpressures are not necessary and virtually complete conversion occurs atnormal atmospheric pressure. Efficient continuous 100% conversion ofacetylene to hydrocarbons has occurred for over 26 hrs at an acetylenespace velocity of 2100 hr⁻¹ and a reaction temperature of 350° C.

Yet another aspect of the invention is a composition which includes thenickel-containing ZSM-5 zeolite catalysts. As used in the presentinvention, nickel content is about 13% and the silica to alumina ratioof the ZSM-5 matrix is between about 30 and 100, preferably with asilica to alumina ratio of about 30. It is understood, however, thatacceptable variations of modified zeolite catalysts might includevarious other metals reasonably accepted as catalysts, such as platinum,palladium, iron and the like. Although demonstrated with ZSM-5, otherzeolites could be employed such as ZSM-11, ZSM-12, ZSM-22, ZSM-23, andthe like. Ratios of silica to alumina in the range of 30 should not beconsidered limiting as reasonable experimentation could determine thatdesirable results, albeit different, are attainable with silica toalumina below 30 or above 100.

Yet another aspect of the invention is a hydrocarbon fuel mixtureproduced by the process described. Generally this mixture will includelower alkyl hydrocarbons, monocyclic aromatic hydrocarbons andparaffins. In most preferred practice, a feedstream comprising acetyleneand water is contacted with a nickel modified zeolite catalyst at atemperature of about 350°-400° C. at atmospheric pressure. A hydrocarbonmixture is produced which has about 30% of its total as monocyclicaromatic hydrocarbons. The aromatic yield remains relatively constantwith time, although there is a slow decrease in the olefin to paraffinratio. The aromatic fraction is almost exclusively monocyclic, typicallycomposed of benzene, toluene, xylenes, and so forth, with less than 3%of the total hydrocarbons being polycyclic compounds.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a comparison of catalytic lifetimes for H-ZSM-5 unmodified(curve A) and modified (curve B) in acetylene conversion.

FIG. 2 shows hydrocarbon product distribution obtained in C₂ H₂conversion as a function of time on-stream.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The invention is a process for highly efficient conversion of alkynefeedstocks to products comprising aromatics, paraffins and olefins.Surprisingly, the combination of a metal modified zeolite catalyst and afeedstock containing a hydrogen donor co-reactant not only provides anefficient conversion of the alkyne but also virtually eliminatescatalyst deactivation. Process efficiency has been maintained near 100%for periods of at least 26 hrs. In contrast, non-zeolite catalysts orzeolite catalysts lacking, as an example, nickel or cobalt, tend torapidly lose efficiency, often within 15 min.

It should be understood that with a reasonable amount of testing,parameters such as temperature, pressure, feedstock combinations, etc.,could be optimized to desired product compositions and ratios. Forexample, the 13.1% Ni/ZSM-5/Al₂ O₃, under conditions specified in Table6 produces over 25% product as an aromatic component, mostly monocyclicaromatics. In the presence of hydrogen, this amount is decreased butthere is an increase in olefinic products. Therefore, product ratios maybe varied in accordance with needs. The role of the added Al₂ O₃ is tofunction primarily as a binder, increasing the available zeolite surfacearea.

In this regard, the nature of the catalyst is expected to have aninfluence on conversions. Other zeolites containing nickel or othertransition metals might be useful in altering compositions, rates orproducts.

While there are numerous process variations, the invention may bepracticed as essentially a single-step conversion of a selectedfeedstock. As an example, acetylene and water are mixed for use in acontinuous feed at 350° C. under normal atmospheric pressure.Selectivity for aromatics is high, over one third of the product, ofwhich one third is toluene.

REACTOR

A fixed-bed continuous flow microreactor operating at atmosphericpressure was packed with catalyst loaded into the center of a 1/4 inch×6inch stainless-steel reactor tubes mounted vertically in a boredcylindrical block aluminum furnace. Reactant gas flows were measuredusing calibrated flow meters. In runs employing liquid reactants (e.g.,H₂ O and/or CH₃ OH), reactant C₂ H₂ gas was bubbled throughthermostatted containers of the liquids. The amount of liquid reactantthus provided as vapor was determined by careful periodic weighing ofthe liquid-containing vessels. All data were acquired using 0.400 g ofcatalyst.

PRODUCT MEASUREMENTS

Reaction products (including any unreacted starting materials) weredetermined by on-line gas chromatography using a capillary GS-Q columnfor mixture separation and a flame ionization detector. The hydrocarbonproducts were identified by comparison of GC retention times with thoseof standard samples. GC response factors for quantitation of productsand reactants were determined from measurements of known amounts of purecompounds. Reaction product distributions were recorded relative toproduct selectivities expressed as carbon atom number.

EXAMPLE 1 Preparation of Ni/ZSM-5/Al₂ O₃

ZSM-5 (for example, as provided by Mobil) with a silicon to aluminumratio of 30 was modified as follows: Na⁺ ions initially present wereexchanged for NH₄ ⁺ using ion-exchange in a (NH₄)₂ SO₄ solution. Theresulting NH₄ -ZSM-5 was dried at 120° C. and subsequently calcined at550° C. for 3 hrs. The resulting H-ZSM-5 catalyst was treated with 0.5 MHNO₃ at 70° C. for 4 hrs, filtered, dried and mixed with Al(OH)₃ powder.The amount of Al(OH)3 employed was adjusted to provide a zeolitecatalyst-aluminum oxide binder ratio of 40:60. The H-ZSM-5/Al₂ O₃mixture was added to a Ni(NO₃)₂ solution, the pH adjusted toapproximately 2 and the resulting solution evaporated to dryness. The Niloading of the final catalyst is determined by the concentration of theNi(NO₃)₂ solution employed. The Ni(NO₃)₂ /H-ZSM-5/Al₂ O₃ mixture wasthen calcined at 550° C. for 2 hrs to convert Ni(NO₃)₂ to nickel oxide.The resulting solid was pelletized, cracked and then screened to 20-40mesh size. Before use, the NiO catalyst component was reduced withhydrogen using a temperature-programmed reduction. The percent Niloading was determined according to the following formula: ##EQU1##

EXAMPLE 2 13.3% Ni/H-ZSM/Al₂ O₃ Catalyzed Conversion of Acetylene

A reactant feed gas of acetylene and water was obtained by bubblingacetylene through a thermostatted vessel containing water. The effluentgas mixture of C₂ H₂ and H₂ O was fed directly to the catalyst,Ni/H-ZSM-5/Al₂ O₃ containing 13.3% Ni relative to the ZSM-5/Al₂ O₃,prepared as described in Example 1, using a heat transfer line toprevent condensation. The reaction was carried out in a fixed-bedcontinuous flow microreactor at 1 atm pressure. The reaction wasconducted for 26 hrs at a C₂ H₂ space velocity of 2100 hr⁻¹ and areaction temperature of 350° C.

FIG. 1, curve B, shows that 100% conversion is maintained for over 26hrs under these conditions. Product distribution, shown in FIG. 2,indicate relative amounts in terms of total olefins, paraffins andaromatics. As shown in FIG. 2, the aromatic yield remained relativelyconstant with time while a slow decrease in olefin/paraffin ratio wasnoted. The aromatic fraction consisted almost exclusively of monocycliccompounds, mainly benzene, toluene, xylenes, etc. with less than 3% oftotal aromatics as polycyclic compounds.

Table 1 illustrates results of using Ni/H-ZSM-5/Al₂ O₃ to convertacetylene to products over a period up to 260 min. In the absence ofadded water, conversion efficiency drastically decreased with time.Although the aromatic yield was initially high, there was a sharpdecrease in percentage yield over time.

                  TABLE 1                                                         ______________________________________                                        Ni/ZSM-5/Al.sub.2 O.sub.3.sup.a catalyzed conversion of                       ______________________________________                                        C.sub.2 H.sub.2                                                               Feed:                                                                         C.sub.2 H.sub.2 (ml/min)                                                                   20      20      20    20    20                                   H.sub.2 O (mg/min)                                                                         0.0     0.0     0.0   0.0   0.0                                  Time on-stream (min)                                                                       10      60      140   200   260                                  Temperature (°C.)                                                                   350     350     350   350   350                                  WHSV (1/hr)  3.2     3.2     3.2   3.2   3.2                                  Conversion (%)                                                                             100.0   22.5    11.4  6.0   2.7                                  Hydrocarbon.sup.b                                                             Distribution (%)                                                              Olefins                                                                       C.sub.2      0.0     0.1     0.1   0.0   0.0                                  C.sub.3      2.6     18.4    23.8  27.1  29.8                                 C.sub.4      2.4     4.7     5.4   6.1   7.2                                  C.sub.5+     1.4     10.4    11.1  12.6  14.0                                 Selectivity (%)                                                                            6.5     33.6    40.3  45.8  51.0                                 Paraffins                                                                     C.sub.1      12.8    3.0     3.5   5.1   6.7                                  C.sub.2      6.2     3.4     2.1   0.9   0.5                                  C.sub.3      7.0     5.7     3.8   2.9   3.4                                  C.sub.4      4.1     4.3     8.9   11.4  13.9                                 C.sub.5+     1.5     5.2     6.8   8.7   10.1                                 Selectivity (%)                                                                            31.6    21.6    25.1  29.0  34.6                                 Aromatics                                                                     Benzene      14.1    2.9     1.5   0.7   0.2                                  Toluene      20.5    8.6     5.4   1.8   0.4                                  Ethyl benzene                                                                              1.4     0.6     0.2   0.1   0.0                                  p + m-Xylene 12.8    10.1    7.4   4.2   1.8                                  o-Xylene     1.7     2.9     1.4   0.7   0.1                                  Ethyl toluene                                                                              2.1     4.3     3.6   2.0   0.3                                  Trimethylbenzene                                                                           3.2     6.2     5.1   2.4   0.8                                  Fused-ring aromatics                                                                       6.2     9.3     10.0  13.3  13.2                                 Selectivity (%)                                                                            62.0    44.9    34.6  25.2  14.4                                 ______________________________________                                         .sup.a 13.1% Ni/HZSM-5 + Al.sub.2 O.sub.3 ZSM5/Al.sub.2 O.sub.3 = 40:60.      .sup.b Percentage based on carbon number of compound.                    

EXAMPLE 3 Comparison of Catalysts for Acetylene Conversion

Various catalysts were used to compare conversion of acetylene to lowerhydrocarbons. Except for the catalyst, experiments were run under thesame conditions described in Example 2. As shown in Tables 2-4, Ni/Al₂O₃, Al₂ O₃, and H-ZSM-5/Al₂ O₃ are not effective catalysts for theconversion of acetylene/water feedstocks to hydrocarbon products.Results using H-ZSM-5 are shown in FIG. 1.

H-ZSM-5 Catalyst

A comparison experiment was conducted using H-ZSM-5 instead ofNi/H-ZSM-5/Al₂ O₃. Results are shown in FIG. 1, curve A. Conversionrates drop to zero after 225 min.

13.1% Ni/Al₂ O₃ Catalyst

Table 2 shows the results of attempting to convert a fixed feed ratio ofacetylene/water to hydrocarbon products with a catalyst which containsNi and Al₂ O₃ but no zeolite. As shown, the present conversion ofacetylene is very small.

                  TABLE 2                                                         ______________________________________                                        Ni/Al.sub.2 O.sub.3 catalyst.sup.a                                            ______________________________________                                        Feed:                                                                         C.sub.2 H.sub.2 (ml/min)                                                                     20         20      20                                          H.sub.2 O (mg/min)                                                                           4.7        4.7     4.7                                         Time on-stream (min)                                                                         15         180     360                                         Temperature (°C.)                                                                     350        350     350                                         WHSV (1/hr)    3.2        3.2     3.2                                         Conversion (%) 2.1        2.0     1.5                                         ______________________________________                                         .sup.a 13.1% Ni/Al.sub.2 O.sub.3.                                        

Al₂ O₃ Catalyst

Table 3 illustrates the conversion of a fixed ratio of acetylene/waterusing Al₂ O₃. Conversion was negligible.

                  TABLE 3                                                         ______________________________________                                        Al.sub.2 O.sub.3 catalyzed conversion of C.sub.2 H.sub.2 /H.sub.2             ______________________________________                                        Feed:                                                                         C.sub.2 H.sub.2 (ml/min)                                                                     20         20      20                                          H.sub.2 O (mg/min)                                                                           4.7        4.7     4.7                                         Time on-stream (min)                                                                         15         180     360                                         Temperature (°C.)                                                                     350        350     350                                         WHSV (1/hr)    3.2        3.2     3.2                                         Conversion (%) 0.4        0.3     0.5                                         ______________________________________                                    

H-ZSM-5/Al₂ O₃ Catalyst

Table 4 shows the conversion of a fixed ratio of acetylene/water usingH-ZSM-5/Al₂ O₃. Initial conversion yields were low and decreased furtherwith time. The majority of products formed were aromatics.

Table 5 indicates initial efficient conversion of acetylene tohydrocarbon products in the presence of water and hydrogen; however,catalyst inactivation is observed in less than one hr of on-streamreaction. In the initial conversion, the majority of products arearomatic. With decreased product yield, paraffins and olefins are themain products detected.

                  TABLE 4                                                         ______________________________________                                        H-ZSM-5/Al.sub.2 O.sub.3.sup.a catalyzed conversion of                        C.sub.2 H.sub.2 /H.sub.2 O                                                    ______________________________________                                        Feed:                                                                         C.sub.2 H.sub.2 (ml/min)                                                                   20.0    20.0    20.0  20.0  20.0                                 H.sub.2 (ml/min)                                                                           0.0     0.0     0.0   0.0   0.0                                  H.sub.2 O (mg/min)                                                                         4.7     4.7     4.7   4.7   4.7                                  Time on-stream (min)                                                                       12      60      120   200   300                                  Reaction     350     350     350   350   350                                  temperature (°C.)                                                      WHSV of C.sub.2 H.sub.2 (1/hr)                                                             3.2     3.2     3.2   3.2   3.2                                  Conversion (%)                                                                             7.2     3.4     2.2   2.0   1.3                                  Hydrocarbon.sup.b                                                             Distribution (%)                                                              Olefins                                                                       C.sub.2      0.1     0.1     0.2   0.1   0.0                                  C.sub.3      0.2     0.1     0.2   0.1   0.1                                  C.sub.4      4.6     4.2     4.3   2.9   2.1                                  C.sub.5+     0.5     0.4     0.4   0.3   0.2                                  Selectivity (%)                                                                            5.4     4.8     5.1   3.4   2.4                                  Paraffins                                                                     C.sub.1      0.1     0.1     0.2   0.0   0.0                                  C.sub.2      0.2     0.1     0.0   0.0   0.0                                  C.sub.3      7.2     6.0     4.2   3.9   3.0                                  C.sub.4      14.5    13.7    12.5  10.4  9.7                                  C.sub.5+     0.7     0.6     0.5   0.4   0.3                                  Selectivity (%)                                                                            22.7    20.5    17.4  14.8  13.0                                 Aromatics                                                                     Benzene      1.2     0.7     0.5   0.3   0.2                                  Toluene      3.8     2.6     2.2   1.3   0.4                                  Ethyl benzene                                                                              0.2     0.1     0.0   0.0   0.0                                  p + m-Xylene 10.4    9.8     8.8   4.2   3.8                                  o-Xylene     1.4     1.2     1.0   0.6   0.4                                  Ethyl toluene                                                                              0.7     0.6     0.5   0.4   0.2                                  Trimethylbenzene                                                                           1.1     1.1     0.9   0.6   0.3                                  Fused-ring aromatics                                                                       53.1    58.6    63.8  74.4  79.3                                 Selectivity (%)                                                                            71.9    74.7    77.7  81.8  84.6                                 ______________________________________                                         .sup.a 0.0% Ni/HZSM-5 + Al.sub.2 O.sub.3 ZSM5/Al.sub.2 O.sub.3 = 40:60.       .sup.b Percentage based on carbon number of compound.                    

                  TABLE 5                                                         ______________________________________                                        H-ZSM-5/Al.sub.2 O.sub.3.sup.a catalyzed conversion of C.sub.2 H.sub.2        /H.sub.2 O/H.sub.2                                                            ______________________________________                                        Feed:                                                                         C.sub.2 H.sub.2 (ml/min)                                                                   5.0     5.0     5.0   5.0   5.0                                  H.sub.2 (ml/min)                                                                           15.0    15.0    15.0  15.0  15.0                                 H.sub.2 O (mg/min)                                                                         2.7     2.7     2.7   2.7   2.7                                  Time on-stream (min)                                                                       15      80      160   240   320                                  Reaction     350     350     350   350   350                                  temperature (°C.)                                                      WHSV of C.sub.2 H.sub.2 (1/hr)                                                             0.8     0.8     0.8   0.8   0.8                                  Conversion (%)                                                                             85.1    12.5    5.4   4.0   2.4                                  Hydrocarbon.sup.b                                                             Distribution (%)                                                              Olefins                                                                       C.sub.2      0.1     0.1     0.2   0.3   0.4                                  C.sub.3      4.8     20.9    24.7  27.9  29.5                                 C.sub.4      4.6     3.2     5.2   5.9   6.9                                  C.sub.5+     3.5     11.4    12.1  12.8  13.7                                 Selectivity (%)                                                                            13.0    35.6    42.2  46.9  50.5                                 Paraffins                                                                     C.sub.1      3.1     2.4     3.2   5.5   6.4                                  C.sub.2      4.4     2.5     1.1   0.7   0.3                                  C.sub.3      6.2     4.0     4.8   3.9   3.0                                  C.sub.4      2.4     5.1     7.9   12.4  13.7                                 C.sub.5+     5.2     5.8     6.9   7.7   9.8                                  Selectivity (%)                                                                            21.3    19.5    23.9  30.2  33.2                                 Aromatics                                                                     Benzene      7.2     1.7     1.3   0.6   0.2                                  Toluene      16.8    4.6     2.4   1.3   0.4                                  Ethyl benzene                                                                              2.1     0.2     0.1   0.0   0.0                                  p + m-Xylene 15.4    17.8    11.4  5.2   1.8                                  o-Xylene     4.8     3.9     1.5   0.4   0.1                                  Ethyl toluene                                                                              5.8     4.3     3.4   1.0   0.3                                  Trimethylbenzene                                                                           6.1     4.2     3.1   1.4   0.8                                  Fused-ring aromatics                                                                       7.6     8.3     10.9  13.3  12.8                                 Selectivity (%)                                                                            65.8    45.0    34.1  23.2  16.3                                 ______________________________________                                         .sup.a ZSM5/Al.sub.2 O.sub.3 = 40:60.                                         .sup.b Percentage based on carbon number of compound.                    

The data in Tables 1-5 illustrate that various catalysts and reactantcombinations employed are not capable of maintaining sustained 100%acetylene conversion for any reasonable length of time-on-streamreaction. These catalysts/reactant combinations are summarized in Table6.

                  TABLE 6                                                         ______________________________________                                        Catalyst   Reactant Feed Activity                                             ______________________________________                                        Ni/ZSM-5/Al.sub.2 O.sub.3                                                                C.sub.2 H.sub.2                                                                             High initial catalytic                                                        activity but rapid                                                            catalytic inactivation                               Ni/Al.sub.2 O.sub.3                                                                      C.sub.2 H.sub.2 + H.sub.2 O                                                                 Negligible catalytic                                 (no ZSM-5)               activity                                             Al.sub.2 O.sub.3                                                                         C.sub.2 H.sub.2 + H.sub.2 O                                                                 Negligible catalytic                                 (no Ni or ZSM-5)         activity                                             ZSM-5/Al.sub.2 O.sub.3                                                                   C.sub.2 H.sub.2 + H.sub.2 O                                                                 Very low initial activity                            (no Ni)                  with continued decrease                                                       in catalytic activity with                                                    time on-stream                                       ZSM-5/Al.sub.2 O.sub.3                                                                   C.sub.2 H.sub.2 + H.sub.2 O + H.sub.2                                                       High initial catalytic                               (no Ni)                  activity but rapid                                                            catalytic inactivation                               ______________________________________                                    

EXAMPLE 4 Effect of Feedstock Modification

Tables 7-14 show results obtained using the conditions described inExample 2 to convert acetylene to a hydrocarbon product, except thatwater, hydrogen, methane, methanol or acetaldehyde combinations wereadded to the feedstock. For comparison, Table 1 shows results obtainedwhen the feedstock is composed only of acetylene without any water.

Table 7 indicates that product distribution is relatively constant andmaintained over a long period when water is added to the hydrocarbonfeedstock.

Table 8 shows variation of the initial product distributions as afunction of the water/acetylene ratio. Product distributions representthose obtained during the first 90 min of the reaction, with theexception of the run with zero added water which represents only 10 minof conversion.

Table 9 illustrates the substitution of methanol for water. Long termstability is obtained. Aromatic product distribution, unlikedistribution with an acetylene and water feedstock, varies with time onstream.

Table 10 shows conversion of acetylene to hydrocarbon products usinggaseous hydrogen in place of water. Aromatic product percent is lessthan half that obtained with water/acetylene feedstocks.

Table 11 illustrates results obtained with water/methanol/acetylenefeedstocks. Product distribution is generally similar to that obtainedwith feedstocks of water/acetylene.

Table 12 shows results with a water/hydrogen/acetylene feedstock. 100%conversion is maintained over the tested period. Product distribution issimilar to those obtained with water/acetylene or methanol/acetylenefeedstocks, notably in aromatic product distribution.

Table 13 indicates that the effect of adding methane to awater/acetylene feedstock reduces aromatic product yield. The high yieldof C₁ paraffin indicates that little of the added methane is consumed.

Table 14 shows results with an acetaldehyde/acetylene feedstock.Essentially complete acetylene conversion is maintained over the listedperiod. Product distribution is similar to that obtained withwater/acetylene or methanol/acetylene feedstocks.

                                      TABLE 7                                     __________________________________________________________________________    Ni/ZSM-5/Al.sub.2 O.sub.3.sup.a catalyzed conversion of C.sub.2 H.sub.2       /H.sub.2 O                                                                    __________________________________________________________________________    Feed:                                                                         C.sub.2 H.sub.2 (ml/min)                                                                  20  20  20  20  20   20                                           H.sub.2 O (mg/min)                                                                        4.7 4.7 4.7 4.7 4.7  4.7                                          Time on-stream (min)                                                                      60  300 600 900 1200 1500                                         Temperature (°C.)                                                                  350 350 350 350 350  350                                          WHSV (1/hr) 3.2 3.2 3.2 3.2 3.2  3.2                                          Conversion (%)                                                                            100 100 100 100 100  100                                          Hydrocarbon.sup.b                                                             Distribution (%)                                                              Olefins                                                                       C.sub.2     0.1 0.0 0.1 0.2 0.1  0.0                                          C.sub.3     1.5 1.7 1.4 0.8 0.3  0.3                                          C.sub.4     0.2 0.2 0.3 0.5 0.2  0.2                                          C.sub.5+    1.5 0.3 0.3 0.4 0.3  0.2                                          Selectivity (%)                                                                           3.3 2.2 2.1 1.9 0.9  0.7                                          Paraffins                                                                     C.sub.1     22.9                                                                              32.6                                                                              41.2                                                                              48.9                                                                              53.5 54.1                                         C.sub.2     17.9                                                                              17.4                                                                              14.8                                                                              11.7                                                                              9.0  8.2                                          C.sub.3     15.8                                                                              13.1                                                                              11.9                                                                              9.7 9.0  9.6                                          C.sub.4     9.4 5.6 2.5 1.1 1.1  0.9                                          C.sub.5+    0.4 0.2 0.2 0.2 0.1  0.1                                          Selectivity (%)                                                                           66.4                                                                              68.9                                                                              70.6                                                                              71.6                                                                              72.7 72.9                                         Aromatics                                                                     Benzene     7.4 7.8 7.9 8.1 9.4  10.5                                         Toluene     10.3                                                                              10.5                                                                              9.3 9.2 8.7  7.9                                          Ethyl benzene                                                                             0.4 0.3 0.3 0.2 0.2  0.1                                          p + m-Xylene                                                                              6.1 4.5 3.7 3.0 2.4  2.1                                          o-Xylene    1.4 1.1 1.0 0.7 0.6  0.5                                          Ethyl toluene                                                                             1.9 1.6 1.4 1.0 0.6  0.3                                          Trimethylbenzene                                                                          2.1 1.9 1.7 1.5 0.7  0.5                                          Fused-ring aromatics                                                                      0.5 1.2 2.2 3.0 3.9  4.5                                          Selectivity (%)                                                                           30.1                                                                              28.9                                                                              27.5                                                                              26.7                                                                              26.5 26.4                                         __________________________________________________________________________     .sup.a 13.1% Ni/HZSM-5 + Al.sub.2 O.sub.3 ZSM5/Al.sub.2 O.sub.3 = 40:60.      .sup.b Percentage based on carbon number of compound.                    

                                      TABLE 8                                     __________________________________________________________________________    Product distributions in presence of Ni/ZSM-5/Al.sub.2 O.sub.3.sup.a          as a function of water/acetylene ratio                                        __________________________________________________________________________    Feed:                                                                         C.sub.2 H.sub.2 (ml/min)                                                                  20  20  20  20   20  20                                           H.sub.2 O (mg/min)                                                                        0.0 1.3 2.7 4.7  9.6 21.6                                         H.sub.2 O/C.sub.2 H.sub.2                                                                 0.00.sup.d                                                                        0.10.sup.c                                                                        0.20.sup.c                                                                        0.37.sup.c                                                                         0.78.sup.c                                                                        1.74.sup.c                                   Temperature (°C.)                                                                  350 350 350 350  350 350                                          WHSV (1/hr) 3.2 3.2 3.2 3.2  3.2 3.2                                          Conversion (%)                                                                            100 100 100 100  100 100                                          Hydrocarbon.sup.b                                                             Distribution (%)                                                              Olefins                                                                       C.sub.2     0.1 0.3 0.2 0.1  0.1 0.0                                          C.sub.3     2.6 0.5 1.4 2.4  0.6 0.7                                          C.sub.4     2.4 0.7 0.7 0.8  0.1 0.5                                          C.sub.5+    1.4 0.5 0.1 0.6  0.2 0.2                                          Selectivity (%)                                                                           6.5 2.0 2.4 3.9  1.0 1.4                                          Paraffins                                                                     C.sub.1     12.8                                                                              53.0                                                                              45.8                                                                              33.1 26.8                                                                              27.4                                         C.sub.2     6.2 11.1                                                                              12.8                                                                              14.4 15.8                                                                              16.4                                         C.sub.3     7.0 10.0                                                                              12.5                                                                              13.1 14.3                                                                              15.2                                         C.sub.4     4.1 2.4 3.1 5.9  8.2 9.0                                          C.sub.5+    1.5 0.3 0.2 0.5  0.3 0.7                                          Selectivity (%)                                                                           31.6                                                                              76.8                                                                              74.4                                                                              67.0 65.4                                                                              68.7                                         Aromatics                                                                     Benzene     14.1                                                                              6.0 7.1 6.7  5.6 6.6                                          Toluene     20.5                                                                              6.2 7.7 10.4 11.9                                                                              11.3                                         Ethyl benzene                                                                             1.4 0.1 0.5 0.6  1.4 1.0                                          p + m-Xylene                                                                              12.8                                                                              2.5 3.4 4.2  7.8 5.8                                          o-Xylene    1.7 0.4 0.8 1.0  1.1 1.5                                          Ethyl toluene                                                                             2.1 0.8 0.9 2.6  2.8 1.2                                          Trimethylbenzene                                                                          3.2 1.1 0.6 2.7  2.5 2.2                                          Fused-ring aromatics                                                                      6.2 4.4 2.4 1.0  0.6 0.3                                          Selectivity (%)                                                                           62.0                                                                              21.5                                                                              23.4                                                                              29.2 33.7                                                                              29.9                                         __________________________________________________________________________     .sup.a 13.1% Ni/HZSM-5 + Al.sub.2 O.sub.3 ZSM5/Al.sub.2 O.sub.3 = 40:60.      .sup.b Percentage based on carbon number of compound.                         .sup.c Time on stream: 90 min.                                                .sup.d time on stream: 10 min.                                           

                                      TABLE 9                                     __________________________________________________________________________    Ni/ZSM-5/Al.sub.2 O.sub.3.sup.a catalyzed conversion of C.sub.2 H.sub.2       /CH.sub.3 OH                                                                  __________________________________________________________________________    Feed:                                                                         C.sub.2 H.sub.2 (ml/min)                                                                  20  20  20  20   20  20                                           CH.sub.3 OH (mg/min)                                                                      22  22  22  22   22  22                                           Time on-stream (min)                                                                      15  80  180 260  380 480                                          Temperature (°C.)                                                                  350 350 350 350  350 350                                          WHSV of C.sub.2 H.sub.2 (1/hr)                                                            3.2 3.2 3.2 3.2  3.2 3.2                                          Conversion (%)                                                                            100 100 100 100  100 100                                          Hydrocarbon.sup.b                                                             Distribution (%)                                                              Olefins                                                                       C.sub.2     0.1 0.1 0.2 0.1  0.1 0.0                                          C.sub.3     1.0 1.5 2.5 2.5  1.4 1.5                                          C.sub.4     1.2 1.2 1.5 1.1  0.6 0.4                                          C.sub.5+    1.0 1.1 0.8 0.3  0.1 0.2                                          Selectivity (%)                                                                           3.1 3.9 5.0 4.0  2.2 2.1                                          Paraffins                                                                     C.sub.1     13.4                                                                              16.5                                                                              23.9                                                                              40.7 54.4                                                                              59.5                                         C.sub.2     21.0                                                                              19.1                                                                              18.1                                                                              14.4 11.4                                                                              10.4                                         C.sub.3     15.1                                                                              14.9                                                                              15.3                                                                              12.7 11.2                                                                              9.7                                          C.sub.4     12.1                                                                              12.4                                                                              8.4 3.5  2.1 1.8                                          C.sub.5+    5.1 4.9 2.4 0.7  0.3 0.2                                          Selectivity (%)                                                                           66.7                                                                              67.8                                                                              68.1                                                                              72.0 79.4                                                                              81.6                                         Aromatics                                                                     Benzene     3.2 2.8 2.7 1.8  1.2 1.0                                          Toluene     9.7 8.5 8.0 5.3  3.4 3.1                                          Ethyl benzene                                                                             0.7 0.5 0.3 0.2  0.1 0.0                                          p + m-Xylene                                                                              9.1 8.3 7.1 5.6  4.3 3.5                                          o-Xylene    1.6 1.6 1.7 1.9  1.5 1.2                                          Ethyl toluene                                                                             1.0 0.8 0.9 0.9  0.8 0.6                                          Trimethylbenzene                                                                          2.8 2.7 2.9 3.5  1.9 1.5                                          Fused-ring aromatics                                                                      2.0 3.2 3.5 4.9  5.3 5.4                                          Selectivity (%)                                                                           30.1                                                                              28.4                                                                              27.1                                                                              24.1 18.5                                                                              16.3                                         __________________________________________________________________________     .sup.a 13.1% Ni/HZSM-5 + Al.sub.2 O.sub.3 ZSM5/Al.sub.2 O.sub.3 = 40:60.      .sup.b Percentage based on carbon number of compound.                    

                                      TABLE 10                                    __________________________________________________________________________    Ni/ZSM-5/Al.sub.2 O.sub.3.sup.a catalyzed conversion of C.sub.2 H.sub.2       /H.sub.2 O/H.sub.2                                                            __________________________________________________________________________    Feed:                                                                         C.sub.2 H.sub.2 (ml/min)                                                                  5.0 5.0 5.0 5.0  5.0 5.0                                          H.sub.2 (mg/min)                                                                          15.0                                                                              15.0                                                                              15.0                                                                              15.0 15.0                                                                              15.0                                         H.sub.2 O (mg/min)                                                                        0.0 0.0 0.0 0.0  0.0 0.0                                          Time on-stream (min)                                                                      15  80  160 240  360 480                                          Temperature (°C.)                                                                  350 350 350 350  350 350                                          WHSV of C.sub.2 H.sub.2 (1/hr)                                                            0.8 0.8 0.8 0.8  0.8 0.8                                          Conversion (%)                                                                            100 100 99.4                                                                              99.0 98.5                                                                              98.0                                         Hydrocarbon.sup.b                                                             Distribution (%)                                                              Olefins                                                                       C.sub.2     0.1 0.1 0.2 0.1  0.0 0.0                                          C.sub.3     2.8 3.0 3.7 4.2  4.9 5.1                                          C.sub.4     9.0 8.7 9.1 8.5  9.1 9.2                                          C.sub.5+    6.2 6.8 7.0 6.2  5.9 5.5                                          Selectivity (%)                                                                           18.1                                                                              18.6                                                                              20.0                                                                              19.0 19.9                                                                              19.8                                         Paraffins                                                                     C.sub.1     17.9                                                                              17.2                                                                              18.0                                                                              17.2 18.5                                                                              18.9                                         C.sub.2     25.4                                                                              25.6                                                                              25.2                                                                              25.9 26.0                                                                              26.5                                         C.sub.3     12.8                                                                              12.5                                                                              11.9                                                                              11.9 11.1                                                                              11.5                                         C.sub.4     8.5 8.2 8.2 9.4  8.1 7.2                                          C.sub.5+    3.7 4.4 3.1 3.0  2.4 1.8                                          Selectivity (%)                                                                           68.5                                                                              67.9                                                                              66.4                                                                              67.4 66.1                                                                              65.9                                         Aromatics                                                                     Benzene     1.8 1.7 1.4 1.2  0.9 0.7                                          Toluene     5.2 5.1 4.8 4.2  2.6 2.2                                          Ethyl benzene                                                                             0.2 0.1 0.1 0.2  0.1 0.1                                          p + m-Xylene                                                                              3.4 3.5 3.8 4.0  4.1 4.5                                          o-Xylene    0.8 0.9 0.7 0.6  0.5 0.6                                          Ethyl toluene                                                                             0.7 0.7 0.5 0.6  0.7 0.6                                          Trimethylbenzene                                                                          0.5 0.6 1.0 1.2  1.6 1.8                                          Fused-ring aromatics                                                                      0.9 1.0 1.5 1.7  3.5 3.8                                          Selectivity (%)                                                                           13.5                                                                              13.6                                                                              13.8                                                                              13.7 14.0                                                                              14.3                                         __________________________________________________________________________     .sup.a 13.1% Ni/HZSM-5 + Al.sub.2 O.sub.3 ZSM5/Al.sub.2 O.sub.3 = 40:60.      .sup.b Percentage based on carbon number of compound.                    

                                      TABLE 11                                    __________________________________________________________________________    Ni/ZSM-5/Al.sub.2 O.sub.3.sup.a catalyzed conversion of C.sub.2 H.sub.2       /CH.sub.3 OH/H.sub.2 O                                                        __________________________________________________________________________    Feed:                                                                         C.sub.2 H.sub.2 (ml/min)                                                                  20  20  20  20   20  20                                           CH.sub.3 OH (mg/min)                                                                      12.8                                                                              12.8                                                                              12.8                                                                              12.8 12.8                                                                              12.8                                         H.sub.2 O (mg/min)                                                                        1.8 1.8 1.8 1.8  1.8 1.8                                          Time on-stream (min)                                                                      15  80  180 260  380 480                                          Temperature (°C.)                                                                  350 350 350 350  350 350                                          WHSV of C.sub.2 H.sub.2 (1/hr)                                                            3.2 3.2 3.2 3.2  3.2 3.2                                          Conversion (%)                                                                            100 100 100 100  100 100                                          Hydrocarbon.sup.b                                                             Distribution (%)                                                              Olefins                                                                       C.sub.2     0.1 0.1 0.0 0.1  0.0 0.0                                          C.sub.3     2.1 2.5 1.8 0.6  0.5 0.6                                          C.sub.4     2.0 1.4 0.7 0.4  0.2 0.0                                          C.sub.5+    1.7 0.8 0.2 0.1  0.0 0.0                                          Selectivity (%)                                                                           5.9 4.8 2.7 1.2  0.7 0.8                                          Paraffins                                                                     C.sub.1     12.4                                                                              23.7                                                                              42.5                                                                              54.1 57.8                                                                              61.3                                         C.sub.2     15.6                                                                              17.3                                                                              15.2                                                                              10.3 8.9 6.5                                          C.sub.3     14.8                                                                              18.5                                                                              11.8                                                                              9.4  8.0 7.1                                          C.sub.4     15.7                                                                              6.8 2.7 1.4  1.3 0.8                                          C.sub.5+    7.7 1.8 0.6 0.2  0.2 0.1                                          Selectivity (%)                                                                           66.2                                                                              68.1                                                                              72.8                                                                              75.4 76.2                                                                              75.8                                         Aromatics                                                                     Benzene     3.5 3.3 3.4 4.1  4.3 4.2                                          Toluene     9.8 8.5 7.3 6.7  6.8 6.9                                          Ethyl benzene                                                                             0.4 0.2 0.1 0.1  0.2 0.1                                          p + m-Xylene                                                                              7.4 7.2 6.6 4.8  4.5 4.3                                          o-Xylene    1.8 1.7 1.7 1.3  1.2 1.5                                          Ethyl toluene                                                                             1.2 1.6 0.5 0.6  0.7 0.3                                          Trimethylbenzene                                                                          2.2 2.3 2.2 2.1  0.6 0.4                                          Fused-ring aromatics                                                                      1.7 2.4 2.7 3.8  4.8 5.7                                          Selectivity (%)                                                                           28.1                                                                              27.2                                                                              24.5                                                                              23.5 23.1                                                                              23.4                                         __________________________________________________________________________     .sup.a 13.1% Ni/HZSM-5 + Al.sub.2 O.sub.3 ZSM5/Al.sub.2 O.sub.3 = 40:60.      .sup.b Percentage based on carbon number of compound.                    

                                      TABLE 12                                    __________________________________________________________________________    Ni/ZSM-5/Al.sub.2 O.sub.3.sup.a catalyzed conversion of C.sub.2 H.sub.2       /H.sub.2 /H.sub.2 O                                                           __________________________________________________________________________    Feed:                                                                         C.sub.2 H.sub.2 (ml/min)                                                                  5.0 5.0 5.0 5.0  5.0 5.0                                          H.sub.2 (ml/min)                                                                          15.0                                                                              15.0                                                                              15.0                                                                              15.0 15.0                                                                              15.0                                         H.sub.2 O (mg/min)                                                                        2.7 2.7 2.7 2.7  2.7 2.7                                          Time on-stream (min)                                                                      15  100 240 360  480 660                                          Temperature (°C.)                                                                  350 350 350 350  350 350                                          WHSV of C.sub.2 H.sub.2 (1/hr)                                                            0.8 0.8 0.8 0.8  0.8 0.8                                          Conversion (%)                                                                            100 100 100 100  100 100                                          Hydrocarbon.sup.b                                                             Distribution (%)                                                              Olefins                                                                       C.sub.2     0.1 0.2 0.1 0.2  0.1 0.0                                          C.sub.3     0.7 0.5 0.6 0.6  0.7 0.6                                          C.sub.4     0.5 0.6 0.6 0.4  0.4 0.5                                          C.sub.5+    0.2 0.4 0.2 0.1  0.2 0.2                                          Selectivity (%)                                                                           1.5 1.5 1.4 1.3  1.4 1.3                                          Paraffins                                                                     C.sub.1     25.4                                                                              25.6                                                                              26.1                                                                              26.2 26.4                                                                              26.5                                         C.sub.2     23.6                                                                              23.8                                                                              24.0                                                                              23.5 23.4                                                                              23.2                                         C.sub.3     12.0                                                                              13.8                                                                              13.7                                                                              13.9 13.7                                                                              13.6                                         C.sub.4     12.4                                                                              12.2                                                                              12.0                                                                              12.8 12.3                                                                              12.8                                         C.sub.5+    0.4 0.5 0.3 0.4  0.5 0.6                                          Selectivity (%)                                                                           75.8                                                                              75.9                                                                              77.1                                                                              76.8 77.3                                                                              76.7                                         Aromatics                                                                     Benzene     3.8 3.7 3.6 3.6  3.5 3.3                                          Toluene     7.7 7.6 7.5 7.6  7.5 7.4                                          Ethyl benzene                                                                             0.2 0.2 0.1 0.1  0.2 0.3                                          p + m-Xylene                                                                              4.6 4.5 4.7 4.6  4.4 4.7                                          o-Xylene    1.0 0.9 0.8 0.8  0.9 0.9                                          Ethyl toluene                                                                             0.5 0.7 0.8 0.8  0.7 0.5                                          Trimethylbenzene                                                                          4.5 4.6 3.8 4.1  3.9 4.2                                          Fused-ring aromatics                                                                      0.5 0.4 0.2 0.5  0.7 0.7                                          Selectivity (%)                                                                           22.8                                                                              22.6                                                                              21.5                                                                              22.1 21.4                                                                              22.0                                         __________________________________________________________________________     .sup.a 13.1% Ni/HZSM-5 + Al.sub.2 O.sub.3 ZSM5/Al.sub.2 O.sub.3 = 40:60.      .sup.b Percentage based on carbon number of compound.                    

                                      TABLE 13                                    __________________________________________________________________________    Ni/ZSM-5/Al.sub.2 O.sub.3.sup.a catalyzed conversion of C.sub.2 H.sub.2       /CH.sub.4 /H.sub.2 O                                                          __________________________________________________________________________    Feed:                                                                         C.sub.2 H.sub.2 (ml/min)                                                                  10  10  10  10   10  10                                           CH.sub.4 (mg/min)                                                                         10  10  10  10   10  10                                           H.sub.2 O (mg/min)                                                                        4.1 4.1 4.1 4.1  4.1 4.1                                          Time on-stream (min)                                                                      15  80  180 260  380 480                                          Temperature (°C.)                                                                  350 350 350 350  350 350                                          WHSV of C.sub.2 H.sub.2                                                                   1.6 1.6 1.6 1.6  1.6 1.6                                          Conversion (%)                                                                            100 100 100 100  100 100                                          Hydrocarbon.sup.b                                                             Distribution (%)                                                              Olefins                                                                       C.sub.2     0.1 0.1 0.0 0.0  0.0 0.0                                          C.sub.3     0.5 0.4 0.1 0.1  0.2 0.3                                          C.sub.4     0.4 0.2 0.2 0.3  0.2 0.1                                          C.sub.5+    0.1 0.0 0.0 0.0  0.0 0.0                                          Selectivity (%)                                                                           1.1 0.7 0.3 0.4  0.4 0.4                                          Paraffins                                                                     C.sub.1     67.6                                                                              79.9                                                                              82.4                                                                              82.9 84.9                                                                              85.9                                         C.sub.2     6.3 4.1 3.7 3.5  3.1 3.1                                          C.sub.3     4.4 2.8 2.4 2.0  1.6 1.8                                          C.sub.4     4.0 1.4 0.9 0.7  0.3 0.3                                          C.sub.5+    0.2 0.2 0.2 0.1  0.0 0.0                                          Selectivity (%)                                                                           82.5                                                                              88.4                                                                              89.6                                                                              89.2 89.9                                                                              91.1                                         Aromatics                                                                     Benzene     3.7 2.9 2.8 2.7  3.3 3.6                                          Toluene     5.8 3.5 3.1 3.0  3.6 2.9                                          Ethyl benzene                                                                             0.4 0.2 0.1 0.0  0.0 0.0                                          p + m-Xylene                                                                              2.2 1.1 0.9 0.9  0.8 0.6                                          o-Xylene    0.7 0.3 0.3 0.4  0.3 0.2                                          Ethyl toluene                                                                             0.9 0.1 0.2 0.3  0.2 0.1                                          Trimethylbenzene                                                                          2.2 1.2 1.1 1.1  0.4 0.4                                          Fused-ring aromatics                                                                      0.5 1.6 1.5 1.4  1.1 0.7                                          Selectivity (%)                                                                           16.4                                                                              10.9                                                                              10.0                                                                              9.8  9.7 8.5                                          __________________________________________________________________________     .sup.a 13.1% Ni/HZSM-5 + Al.sub.2 O.sub.3 ZSM5/Al.sub.2 O.sub.3 = 40:60.      .sup.b Percentage based on carbon number of compound.                    

                  TABLE 14                                                        ______________________________________                                        Ni/ZSM-5/Al.sub.2 O.sub.3.sup.a catalyzed conversion of C.sub.2 H.sub.2       /CH.sub.3 CHO                                                                 ______________________________________                                        Feed:                                                                         C.sub.2 H.sub.2 (ml/min)                                                                   20      20      20    20    20                                   CH.sub.3 CHO (mg/min)                                                                      17.6    17.6    17.6  17.6  17.6                                 Time on-stream (min)                                                                       15      80      200   300   420                                  Temperature (°C.)                                                                   350     350     350   350   350                                  WHSV of C.sub.2 H.sub.2                                                                    1.6     1.6     1.6   1.6   1.6                                  Conversion (%)                                                                             98.9    99.1    100.0 100.0 100.0                                Hydrocarbon.sup.b                                                             Distribution (%)                                                              Olefins                                                                       C.sub.2      0.5     0.7     0.4   0.3   0.2                                  C.sub.3      5.6     4.4     1.8   0.7   0.5                                  C.sub.4      5.2     4.3     2.1   2.1   1.5                                  C.sub.5+     2.1     2.5     2.0   0.4   0.2                                  Selectivity (%)                                                                            13.4    11.9    6.3   3.5   2.4                                  Paraffins                                                                     C.sub.1      37.0    40.7    49.9  50.1  51.3                                 C.sub.2      10.3    11.5    9.3   7.8   8.5                                  C.sub.3      11.1    10.1    10.3  12.4  12.3                                 C.sub.4      2.2     2.5     1.4   3.0   4.0                                  C.sub.5+     1.9     1.1     1.2   0.3   0.3                                  Selectivity (%)                                                                            62.5    65.0    72.1  74.4  76.1                                 Aromatics                                                                     Benzene      4.2     3.7     3.7   5.1   5.0                                  Toluene      11.5    10.2    8.4   8.6   8.3                                  Ethyl benzene                                                                              0.7     0.5     0.6   0.5   0.4                                  p +  m-Xylene                                                                              3.9     4.2     6.4   4.9   5.0                                  o-Xylene     1.1     1.0     0.8   1.2   1.0                                  Ethyl toluene                                                                              1.5     1.5     0.6   0.5   0.5                                  Trimethylbenzene                                                                           0.5     0.6     0.4   0.3   0.4                                  Fused-ring aromatics                                                                       0.7     0.8     0.7   1.0   0.9                                  Selectivity (%)                                                                            24.1    23.1    21.6  22.1  21.5                                 ______________________________________                                         .sup.a 13.1% Ni/HZSM-5 + Al.sub.2 O.sub.3 ZSM5/Al.sub.2 O.sub.3 = 40:60.      .sup.b Percentage based on carbon number of compound.                    

The data in Tables 7 -14 show that in the presence of hydrogen donatingadded co-reactant and a Ni/H-ZSM-5/Al₂ O₃ catalyst, acetylene isefficiently and continuously converted to hydrocarbon products. In theabsence of water, initial conversion is complete but falls rapidly withtime (see Table 1).

EXAMPLE 5 Co/H-ZSM-5/Al₂ O₃ Catalyst

Acetylene/water feedstocks were catalytically converted to olefins,paraffins and aromatics under the conditions described in Example 2except that a 13.1% cobalt-containing catalyst was used in place of thenickel-loaded catalyst. Results are shown in Table 15. The conversionrate was equally efficient as the Ni catalyst, see Table 8, butselectivity was different in that overall yield of aromatics was lowerwhen cobalt-containing catalyst was used.

                                      TABLE 15                                    __________________________________________________________________________    Product distribution in the Co/H-ZSM-5/Al.sub.2 O.sub.3.sup.a                 catalyzed conversion of C.sub.2 H.sub.2 /H.sub.2 O                            __________________________________________________________________________    Feed:                                                                         C.sub.2 H.sub.2 (ml/min)                                                                  20  20  20  20   20  20                                           H.sub.2 O (mg/min)                                                                        4.7 4.7 4.7 4.7  4.7 4.7                                          Time on-stream (min)                                                                      15  80  180 260  380 480                                          Temperature (°C.)                                                                  350 350 350 350  350 350                                          WHSV (1/hr) 3.2 3.2 3.2 3.2  3.2 3.2                                          Conversion (%)                                                                            100 100 100 100  100 100                                          Hydrocarbon.sup.b                                                             Distribution (%)                                                              Olefins                                                                       C.sub.2     0.2 0.1 0.2 0.1  0.0 0.0                                          C.sub.3     0.6 0.2 0.3 0.2  0.3 0.3                                          C.sub.4     0.4 0.2 0.2 0.1  0.2 0.2                                          C.sub.5+    0.1 0.0 0.0 0.0  0.0 0.0                                          Selectivity (%)                                                                           1.3 0.5 0.7 0.4  0.5 0.5                                          Paraffins                                                                     C.sub.1     62.4                                                                              67.3                                                                              71.5                                                                              75.5 77.3                                                                              77.3                                         C.sub.2     11.0                                                                              10.2                                                                              9.2 7.7  7.6 7.8                                          C.sub.3     6.0 4.7 4.0 2.8  2.6 2.6                                          C.sub.4     1.4 0.7 0.9 0.9  0.5 0.5                                          C.sub.5+    0.3 0.2 0.2 0.2  0.1 0.0                                          Selectivity (%)                                                                           81.1                                                                              83.1                                                                              85.8                                                                              87.1 88.1                                                                              88.2                                         Aromatics                                                                     Benzene     2.4 3.5 3.7 3.9  4.1 4.7                                          Toluene     4.7 6.1 5.2 4.8  4.4 4.3                                          Ethyl benzene                                                                             0.2 0.2 0.1 0.1  0.0 0.0                                          p + m-Xylene                                                                              3.3 3.5 2.3 2.0  1.7 1.2                                          o-Xylene    0.5 0.8 0.7 0.6  0.5 0.2                                          Ethyl toluene                                                                             3.6 0.7 0.5 0.4  0.2 0.3                                          Trimethylbenzene                                                                          2.4 1.2 0.8 0.5  0.3 0.5                                          Fused-ring aromatics                                                                      0.5 0.4 0.2 0.2  0.2 0.1                                          Selectivity (%)                                                                           17.6                                                                              16.4                                                                              13.8                                                                              12.5 11.4                                                                              11.3                                         __________________________________________________________________________     .sup.a 13.1% Co/HZSM-5 + Al.sub.2 O.sub.3 HZSM-5/Al.sub.2 O.sub.3 = 40:60     .sup.b Percentage based on carbon number of compound.                    

EXAMPLE 6 Effect of Temperature on Catalyzed Conversion of Acetylene

A fixed ratio water/acetylene feedstock was converted to hydrocarbonproducts under the conditions described in Example 2, except thatreaction temperature was varied over a range of 200°-500° C. As shown inTable 16, optimal temperatures for complete conversion were at or above350° C. A desirable aromatic content in terms of product distribution isobserved at an optimal temperature near 350° C. under reactionconditions used in this example.

                                      TABLE 16                                    __________________________________________________________________________    Product distribution as a function of reaction temperature                    in the Ni/ZSM-5/Al.sub.2 O.sub.3.sup.a catalyzed conversion of C.sub.2        H.sub.2 /H.sub.2 O                                                            __________________________________________________________________________    Feed:                                                                         C.sub.2 H.sub.2 (ml/min)                                                                  20  20  20  20   20  20  20                                       H.sub.2 O (mg/min)                                                                        4.7 4.7 4.7 4.7  4.7 4.7 4.7                                      Temperature (°C.)                                                                  200 250 300 350  400 450 500                                      WHSV (1/hr) 3.2 3.2 3.2 3.2  3.2 3.2 3.2                                      Conversion (%)                                                                            64.9                                                                              82.2                                                                              95.1                                                                              100  100 100 100                                      Hydrocarbon.sup.b                                                             Distribution (%)                                                              Olefins                                                                       C.sub.2     0.3 0.2 0.1 0.2  0.1 0.2 0.2                                      C.sub.3     47.7                                                                              38.8                                                                              36.5                                                                              14.3 8.4 3.8 0.2                                      C.sub.4     5.5 3.5 1.2 1.4  0.3 0.1 0.2                                      C.sub.5+    2.5 1.1 0.4 2.2  0.1 0.0 0.1                                      Selectivity (%)                                                                           56.0                                                                              43.6                                                                              38.2                                                                              18.1 8.9 4.1 0.7                                      Paraffins                                                                     C.sub.1     18.7                                                                              21.9                                                                              23.0                                                                              23.7 50.1                                                                              66.4                                                                              86.9                                     C.sub.2     7.1 15.5                                                                              20.2                                                                              16.5 8.9 5.5 1.1                                      C.sub.3     1.1 0.9 0.6 2.2  1.7 0.5 0.0                                      C.sub.4     12.1                                                                              13.4                                                                              11.2                                                                              8.7  1.8 0.5 0.3                                      C.sub.5+    3.4 1.2 0.7 1.1  0.8 0.2 0.0                                      Selectivity (%)                                                                           43.3                                                                              52.9                                                                              55.7                                                                              52.2 63.3                                                                              73.1                                                                              88.3                                     Aromatics                                                                     Benzene     0.6 1.0 2.4 7.6  8.1 5.7 0.6                                      Toluene     0.4 0.9 2.0 11.0 7.9 3.2 0.3                                      Ethyl benzene                                                                             0.0 0.0 0.0 0.4  0.1 0.0 0.0                                      p + m-Xylene                                                                              0.3 0.6 0.8 6.5  2.3 1.1 0.2                                      o-Xylene    0.0 0.1 0.2 1.4  1.2 0.2 0.1                                      Ethyl toluene                                                                             0.4 0.8 0.3 1.1  2.7 3.1 2.4                                      Trimethylbenzene                                                                          0.1 0.2 0.3 1.3  4.2 6.7 3.5                                      Fused-ring aromatics                                                                      0.1 0.1 0.2 0.6  1.4 3.0 4.1                                      Selectivity (%)                                                                           1.9 3.7 6.2 29.9 27.9                                                                              23.0                                                                              11.2                                     __________________________________________________________________________     .sup.a 13.1% Ni/HZSM-5 + Al.sub.2 O.sub.3 ZSM5/Al.sub.2 O.sub.3 = 40:60.      .sup.b Percentage based on carbon number of compound.                    

EXAMPLE 7 Effect of Nickel Content on Catalyst Efficiency

The effect of varying the nickel content of the Ni/H-ZSM-5/Al₂ O₃catalyst is shown in Table 17. Catalyst was prepared as described inExample 1, using different concentrations of Ni(NO₃)₂ solutions toprovide variations in percent Ni loading. Results indicate a substantialincrease in the percent acetylene conversion for nickel loadings above5% under the particular reaction conditions employed.

                                      TABLE 17                                    __________________________________________________________________________    Product distribution and C.sub.2 H.sub.2 conversion efficiency as a           function                                                                      of Ni loading of ZSM-5/Al.sub.2 O.sub.3.sup.a catalyst                        __________________________________________________________________________    Feed:                                                                         C.sub.2 H.sub.2 (ml/min)                                                                  20  20  20  20   20  20                                           H.sub.2 O (mg/min)                                                                        4.7 4.7 4.7 4.7  4.7 4.7                                          Ni content (%)                                                                            0.0 5.0 10.0                                                                              13.2 20.0                                                                              35.0                                         Temperature (°C.)                                                                  350 350 350 350  350 350                                          WHSV (1/hr) 3.2 3.2 3.2 3.2  3.2 3.2                                          Conversion (%)                                                                            2.2 4.3 99.1                                                                              100  100 100                                          Hydrocarbon.sup.b                                                             Distribution (%)                                                              Olefins                                                                       C.sub.2     0.2 0.1 0.9 0.0  0.2 0.2                                          C.sub.3     0.2 0.2 1.8 1.5  0.6 0.5                                          C.sub.4     4.3 2.0 7.0 0.2  0.4 0.4                                          C.sub.5+    0.4 2.2 7.4 1.5  0.1 0.2                                          Selectivity (%)                                                                           5.1 4.5 17.1                                                                              3.2  1.3 1.3                                          Paraffins                                                                     C.sub.1     0.2 4.2 24.5                                                                              24.9 36.6                                                                              32.9                                         C.sub.2     0.0 0.4 21.0                                                                              16.9 15.0                                                                              17.6                                         C.sub.3     4.2 11.4                                                                              13.4                                                                              14.8 10.8                                                                              10.5                                         C.sub.4     12.5                                                                              15.1                                                                              1.6 9.4  4.5 5.4                                          C.sub.5+    0.5 0.6 4.8 0.4  0.5 1.2                                          Selectivity (%)                                                                           17.4                                                                              31.7                                                                              65.3                                                                              66.4 67.4                                                                              67.6                                          Aromatics                                                                    Benzene     0.5 6.1 5.6 7.4  11.9                                                                              9.7                                          Toluene     2.2 4.7 5.1 10.3 12.0                                                                              13.6                                         Ethyl benzene                                                                             0.0 0.0 0.2 0.4  0.4 0.5                                          p + m-Xylene                                                                              8.8 1.2 3.1 6.1  2.5 3.3                                          o-Xylene    1.0 0.5 0.8 1.4  0.9 0.6                                          Ethyl toluene                                                                             0.5 0.2 0.7 1.9  1.5 1.2                                          Trimethylbenzene                                                                          0.9 1.1 1.2 2.1  1.4 1.4                                          Fused-ring aromatics                                                                      63.8                                                                              50.0                                                                              0.9 0.5  0.7 0.8                                          Selectivity (%)                                                                           77.7                                                                              63.8                                                                              17.6                                                                              30.4 31.3                                                                              31.1                                         __________________________________________________________________________     .sup.a Ni/HZSM-5 + Al.sub.2 O.sub.3 HZSM-5/Al.sub.2 O.sub.3 = 40:60. Time     on stream: 120 min.                                                           .sup.b Percentage based on carbon number of compound.                    

REFERENCES

The references cited within the text are incorporated herein byreference to the extent they supplement, explain, provide a backgroundfor or teach methodology, techniques and/or compositions employedherein.

1. Allenger, V. M., Brown, J. R., Clugston, D., Ternan and McLean, D.D., Appl. Cat., 39, 191-211 (1988).

2. Allenger, V. M., Fairbridge, C., McLean, D. D., and Ternan, M., J.Catal., 105, 71-80 (1987).

3. Allenger, V. M., McLean, D. D. and Ternan, M., Fuel, 66, 435-436(1987).

4. Chevreau, T., Cornet, D., Marzin, M. and Roudias, K., Bull. Soc.Chim, France, #3, 483-488 (1988).

5. Seddon, D., BHP Technical Bulletin, 27, 84-88 (1983).

6. Seddon, D., Larkins, F. P., and Mole, T., Federal Research inProgress (Dept. of Energy), 1984-1986, "Catalytic conversion of LightHydrocarbons to Liquid Fuels."

7. Tedeschi, R. J. in Acetylene Based Chemicals form Coal and OtherNatural Resources, Marcel Dekker, Inc., New York, N.Y. 10016 (1982).

8. Tsai, P. and Anderson, J. R., J. Catal., 80, 207-214 (1983).

9. White, N., Kagi, D. A., Creer, J. G. and Tsai, P., U.S. Pat. No.4,424,401, Jan. 3, 1984.

Although the present invention has been described in some detail by wayof illustration and example for purposes of clarity and understanding,it will be obvious that certain changes and modifications may bepracticed within the scope of the claims. The present invention has beendescribed in terms of particular embodiments found by the inventors tocomprise preferred modes of practice of the invention. It will beappreciated by those of skill in the art that in light of the presentdisclosure numerous modifications and changes can be made in theparticular embodiments exemplified without departing from the intendedscope of the invention. For example, various modifications of feedstocksare envisioned, including nitrogen or sulfur containing compounds, suchthat selective syntheses of compounds could be effected, for examplearomatic heterocyclics. In a similar vein, although the processdescribed is carried out at atmospheric pressure, one can anticipatesuccessful conversions at pressures both above and below one atmosphere.These and obvious related modifications are contemplated to be withinthe scope of the claims.

What is claimed is:
 1. An efficient process for producing a fuel or fueladditive, comprising the steps:combining an alkyne with a potentialhydrogen donor compound to form a feedstock; obtaining a nickel orcobalt-containing zeolite catalyst wherein the nickel or cobalt is infree-metal form; and contacting said feedstock with said catalyst toproduce a fuel or fuel additive comprising monocyclic aromatichydrocarbons.
 2. The process of claim 1 Wherein the alkyne is propyne,1-butyne or 2-butyne.
 3. The process of claim 1 wherein the alkyne isacetylene.
 4. The process of claim 1 wherein the hydrogen donor compoundis water.
 5. The process of claim 1 wherein the hydrogen donor compoundis a lower molecular weight alcohol.
 6. The process of claim 5 whereinthe lower molecular weight alcohol is methanol.
 7. The process of claim1 wherein the hydrogen donor compound is a lower molecular weightaldehyde.
 8. The process of claim 7 wherein the lower molecular weightaldehyde is acetaldehyde.
 9. The process of claim 7 wherein the lowermolecular weight aldehyde is propionaldehyde.
 10. The process of claim 1wherein the zeolite catalyst is Co/H-ZSM-5/Al₂ O₃.
 11. The process ofclaim 1 wherein the zeolite catalyst is Ni/H-ZSM-5/Al₂ O₃.
 12. Theprocess of claim 11 wherein the zeolite catalyst contains at least 5%Ni.
 13. The process of claim 11 wherein the zeolite catalyst containsabout 13% Ni.
 14. The process of claim 1 wherein the feedstock being atatmospheric pressure, is heated to a temperature between about 300°-400°C.
 15. The process of claim 1 wherein the contacting is for a period oftime effective to provide a hydrocarbon fuel.
 16. A hydrocarbon mixtureproduced by the process of claim
 1. 17. The hydrocarbon mixture of claim16 comprising lower olefins, monocyclic aromatic hydrocarbons, andparaffins.
 18. The hydrocarbon mixture of claim 16 produced bycontacting a feed stream comprising acetylene and water withNi/H-ZSM-5/Al₂ O₃ catalyst at a temperature of about 350°-400° C. atatmospheric pressure.
 19. The hydrocarbon mixture of claim 17 whereinthe monocyclic aromatic hydrocarbons are about 30% of totalhydrocarbons.